This invention relates to magnetic disk drives, and more particularly, to a new magnetic head actuator, having improved bearing life, reduced vibration, and reduced potential servo loop instability.
Recently, magnetic disk drives which write and read digital data from flexible magnetic disks have been extensively used. These are frequently referred to as "floppy" disks and "floppy disk drives". These drives have been extensively used for small, so-called microcomputer, systems for word-processing applications, and the like. Examples of floppy disk drives are shown in U.S. Pat. Nos. 3,990,111--Elliott, 3,678,481--Dalziel, et al, 3,815,150--Stoddard, et al, 4,125,883--Rolph and 4,089,029--Castrodale, et al.
These floppy disk drives normally have a linear magnetic head actuator which steps from track to track of the magnetic disk.
Larger disk drives, such as those used with mini-computer systems, use a rotary actuator which has the same movement as a phonograph tone arm. Examples of such disk drives include the IBM System 32 disk drive. These disk drives have better performance characteristics than the floppy disk drives.
"ROTARY PRINTED CIRCUIT COIL ACTUATOR FOR A MAGNETIC DISK DRIVE", Ser. No. 259,696, filed May 1, 1981, now abandoned, Bauck, describes a rotary actuator in which a planar coil and stationary permanent magnets cooperate to rotate an actuator arm in response to current applied to the coil.
It is an object of the present invention to improve the operating characteristics of this type of actuator.